This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 30 |
| 4 | 226 |
| 5 | 1990 |
| 6 | 19414 |
| 7 | 203455 |
| 8 | 2248355 |
| 9 | 25887399 |
| 10 | 307993015 |
| 11 | 3763786811 |
| 12 | 47032778955 |
| 13 | 598933188955 |
| 14 | 7751562502555 |
| 15 | 101741582076580 |
| 16 | 1351906409905480 |
| 17 | 18159677984049580 |
| 18 | 246298405721739580 |
| 19 | 3369517588450715680 |
| 20 | 46457194476711692080 |